The present invention relates to an adjusting device for the specimen stage of an optical instrument, such as a microscope or a measuring instrument, comprising a base plate and two slides arranged over each other on said base plate, said slides being adjustable in two horizontal coordinate directions by means of adjusting means drivingly connected with coaxial drive means extending in a direction parallel to the optical axis of the instrument.
German published application DE-A No. 2 233 715 discloses a specimen stage with a cross slide for incident light microscopes, wherein the cross slide may be moved by means of two pinion knobs arranged on the underside of the stage coaxially with and parallel to the optical axis. In this arrangement, two slides are supported on a guide plate and may be displaced horizontally in two coordinate directions. The displacement of the two slides is effected by rotation of the two coaxial pinion knobs, the shafts of which are each equipped at their upper ends with a pinion, said pinions each engaging a rack fastened to the slide involved. This known arrangement makes fine adjustment of the position of the object to be observed possible. However, rapid manual adjustment of the slides is not feasible with this arrangement.
German allowed application DE-B No. 1 281 762 discloses a coarse and fine adjusting device for an adjustable member, such as a vernier slide for measuring instruments, microscopes, coordinate boring machines and the like. In this device, a vernier slide displaceable in ball guideways on a base is fixedly joined with a nut member. In the nut member, a threaded ring which serves to bearingly support a round rod, is connected with a fine setting knob and arranged in an axially screwable manner. The rod is displaceable in a pillow block and may be clampingly secured by means of an excentric disk. With the excentric clamp released, the vernier slide may be brought rapidly into its approximate working position by simply pushing the fine adjusting knob, whereby the round rod slides freely in the bores of the legs of the pillow block and the bore of the excentric disk. When the round rod is securely clamped in the bores of the legs of the pillow block by means of the excentric disk, the position of the vernier slide is defined, whereupon a fine adjustment may be effected by rotating the fine adjusting knob connected with the threaded ring through the finely threaded nut member. This device makes it possible to achieve short adjusting times with a high accuracy, but only in one coordinate direction.
In optical instruments, such as microscopes used in the production of semiconductors to verify the exact configuration of masking elements, it is often necessary to displace the stage rapidly over long distances in both coordinate directions. In prior art devices, this requires considerable time.